CVE-2018-20200 in OkHttp
Summary
by MITRE
CertificatePinner.java in OkHttp 3.x through 3.12.0 allows man-in-the-middle attackers to bypass certificate pinning by changing SSLContext and the boolean values while hooking the application.
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Analysis
by VulDB Data Team • 08/06/2024
The vulnerability identified as CVE-2018-20200 resides within the CertificatePinner.java component of OkHttp library versions 3.x through 3.12.0, representing a critical security flaw that undermines the certificate pinning mechanism designed to prevent man-in-the-middle attacks. This vulnerability operates through a sophisticated hooking mechanism that allows attackers to manipulate the SSLContext and boolean values within the application's runtime environment, effectively bypassing the security controls that should protect against certificate validation failures.
The technical flaw exploits the dynamic nature of the Java runtime environment where OkHttp's certificate pinning implementation relies on specific boolean flags and SSLContext configurations that can be modified during application execution. When attackers successfully hook the application, they can alter the underlying SSLContext parameters and manipulate boolean values that control the certificate validation process, thereby allowing malicious certificates to be accepted even when they don't match the pinned certificates. This represents a fundamental weakness in the library's defensive architecture where runtime modifications can override security controls that should be immutable during the certificate validation process.
The operational impact of this vulnerability extends far beyond simple certificate validation bypass, as it fundamentally undermines the trust model that mobile and web applications rely upon for secure communications. Applications using vulnerable versions of OkHttp become susceptible to attacks where attackers can intercept and modify encrypted communications between clients and servers, potentially accessing sensitive data including user credentials, personal information, and financial transactions. The vulnerability is particularly dangerous in mobile applications where users expect their communications to remain private and secure, as it allows attackers to establish trust with malicious intermediaries that would normally be rejected by certificate pinning mechanisms.
Security professionals should understand that this vulnerability aligns with multiple ATT&CK framework techniques including T1059.007 (Command and Scripting Interpreter: PowerShell) and T1555.003 (Credentials from Password Stores: Credentials from Web Browsers) as attackers can leverage hooking mechanisms to manipulate application behavior and extract sensitive information. The vulnerability also corresponds to CWE-295 (Improper Certificate Validation) and CWE-310 (Cryptographic Issues) categories, highlighting the fundamental flaws in how certificate validation is implemented and managed within the affected library. Organizations should immediately upgrade to OkHttp versions beyond 3.12.0 where this vulnerability has been addressed, implement runtime application self-protection mechanisms, and conduct thorough security assessments of applications that may be using vulnerable versions of the library. Additionally, developers should consider implementing additional security controls beyond certificate pinning, such as certificate transparency monitoring and runtime integrity checks to detect and prevent similar hooking attacks from compromising application security.